Control system and device for dynamoelectric machines



- W. R. HOLMES CONTROL SYSTEM AND DEVICE FOR Nov. 27, 1951 2 SHEETS-SHEET l www@ UmN

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CONTROL SYSTEM AND DEVICE EOE DYNMOELECTRIC MACHINES original Filed oci. 1o, 1945 2 SHEETS- SHEET 2 INVENTOR W/LL/HM Ff. HLMEE E l d wie? Z ATTORN EY Patented Nov. 27,Y 1951 CONTROL SYSTEM AND DEVICE FOR DYNAMOELECTRIC MACHINES William R. Holmes, New York, N. Y., assigner to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Original application October 10, 1945, Serial No. 621,515. Divided and this application April l2, 1950, Serial No. 155,437

3 Claims. (C1. -171-118) This application is a vdivision of application Serial No. 621,515, led October l0, 1945, and relates to an automatic control system for a dynamoelectric machine and more particularly to a system for controlling automatically the connection of a dynamoelectric machine to a load circuit.

An object of the invention is to provide a novel relay arrangement for controlling the connecfor each generator;

` Figure 2 is a diagrammatic View of a second lform of the invention and illustrating the operwation thereof.

-AReferring to the drawing, numeral I indicates a generator of conventional type including an armature and commutator 2, shunt field winding 3, and nterpole compensating winding 4.

The generator I has suitable terminals A, B, D and E. The terminal A is connected through a suitable conductor 5 to the shunt field winding 3 while the opposite end of the shunt eld winding 3 is connected through a conductor E to negative output brushes on the commutator 2 tion of each source of electrical energy to the load, suitably interconnected by a conductor 'I. The in which the connection of each source to the commutator 2 has also provided positive output load is dependent first upon the voltage of the brushes suitably interconnected by a conductor source having a predetermined value and sec- 8. rlhe conductor il is connected by a conductor ond upon the voltage of the source exceeding 9 to the positive output generator terminal B, -that of the load by a predetermined differential. while the conductor l is connected by a conduc- Another object of the invention is to provide a tor l to the negative output generator terminovel arrangement for varying the datum or voltnal D. The interpole compensating winding 4 Vage setting of the Voltage regulating means, inpreviously noted is connected between the negacluding novel relay means for connecting the tive conductor I and the generator terminal E. datum changing means of the regulator of a given Leading from the positive output terminal B of vsource of electrical energy in and out of operathe generator I is a conductor H which leads to tive relation, dependent upon the operating cona terminal I2 on a regulator I3 and terminal I4 dition of the source of electrical energy in relaon relay control i5. There also leads from the tion to the load. negative output terminal 'D of the generator I Another object of the invention is to provide a conductor I- which is connected to regulator a novel means for disconnecting the means for terminal Il and relay control terminal I8. -maintaining a predetermined division of load be- Leading from the interpole compensating windtween the sources of electrical energy out of 0ping terminal E of the generator I is a conduc- .erative relation with a given source, upon failure tor I9 which leads to a negative bus line 2. A of said source, so as to thereby automatically positive bus line 2l is connected through a main protect the system against being adversely efcontrol relay switch 22 to the positive output fected by the failure of the source. terminal B by a conductor 23. The relay switch Another object oi the invention is to provide 22 is controlled by an electromagnetic winding temperature responsive means for varying the 24 having one end connected through a ground generator load in accordance with the operating connection 24A to the negative bus line 2G. The temperature of the generator. opposite end of the winding 24 is connected by These and other objects of the invention are a conductor 25 to a terminal 26 of the relay con- Vpointed out in the following description in terms trol I5. There further leads from the negative of the embodiment thereof which is shown in the bus line 20 a conductor 2'1 which connects the accompanying drawings. It is to'be understood, 40 negative bus line 2i! to a regulator terminal 28 however, that the drawings are for the purpose anda control relay terminal 29. of illustration only, and are not designed as a Connected across the control relay terminals definition of the limits of vthe invention. Refer- I4 and 29 or the positive and negative terminals ence being had to the appended claims for this B and E respectively of the generator I is a voltpurpose. age coil 3 and a voltage coil 3| which are con- Referring to the drawing: nected in parallel to the terminal I4 through Figure l is a diagrammatic view of a system a conductor 32 and to the terminal v29 through embodying the present invention in whichasingle conductors 33 and 34 and a rectier 35. Conf/T01 relay and regulator are shown in detail, The voltage coil 3: controls spring tensioned like COI1tr0l1'eleys and regulators being provided 50 switch arms 3S and 36A. The switch arms 3S and 36A close upon energization of the winding 30 by a generator voltage in excess of a predetermined value. The switch arm 36 closes a circuit from conductor 32 through a conductor 31 to a differential winding 38.

The differential winding 38 has one end connected to a relay control terminal 39 while the opposite end is connected to a control contact 48 of the switch 35. The terminal 39 is connected through a conductorlil to the positive bus line 2 I.

Across the positive and negative bus lines 28 and 2| there is connected a battery or load 42 having its negative terminal connected to the negative bus line 28 and its positive terminal connected to the positive bus line 2 I.

The coils 3| and 38 are arranged so as to control the closing of relay spring tensioned switch arm 43 which controls a normally. open switch.

contact 45. The contact 45 is connected to the terminal 26, while the switch arm 43 opens and closes contact 45. The switch arm 431s con'- nected by conductor 41 to conductor 31 Yand through conductors 32 and I I to the positive terminal B of the generator I Thus upon switch arm 43 closing contact 45, the electromagnet 24 `is energized-closingL switch 22 and connecting the k.generator to the bus lines 28 and 2|.

The coil 38 is connectedacross theoutput ter- -minals B and E of generator I and registers the --direct `voltage of generatori and is arranged to .close-switch arms 36Vand 36A at some predeter- 'mined value below the normalvoltage of bus olines A28-and 2l, at for example 28 or 21 volts vand opens at a predetermined value below the vnormal voltagerof the battery 42, at for example 22 too23 volts-.

'---Th'e-coil 3| islikewise connected across the l-outputterminals. Band E of the generator I and .registers the .voltage of generator I. The coil '3| arranged so as not to close relay switchv 4'arm143 below a predetermined voltage, of, for example, 32 to 34 volts, whichvoltage is so selected -as..to always be above the voltage of the bus lines ..28 and 2|.v

The coil 38 is arranged so as to interconnect the/positive terminals of the battery 42 and generator.. I Vuponthe closing of switch V36 so as to register Vthe diierence in voltage between the generator IV and battery 42. The coil 38 is so ar- '.ranged that when the generator voltage exceeds that ofthe battery. 42 or bus lines.28 and 2| by a vpredeterminedvalue, or above for example a 0.5 Ivoltage .diierentiaL the current flow through .coil 38 will bein a direction causing the magnetic force of the differential coil 3 8 to beadded Y to the magnetic force of voltage coil 3| to cause ...switch arm 4 3 to close contact 45. AsV long as the voltage of battery 42 or the voltage of the bus lines 28 and 2| exceeds that ofthe generatorl, the switch 4 3 will not close, since thecurrent flow through c oil 38 will be in l anpposito drootionto ,that previously dosolbod and willvtend to counteract `the electromagnetic forceof the coil 3|. When the switch 22 closes it eiect shunts diierential coil 38 out of loperation. l f Y There is further provided a current coil 48V for controlling the operation of the switch arm 43 jointly with the differential coil 38 upon the closing of switch 36. One end of coil 48 is connected to terminalv I8 whilethe bpposite end is connected to terminal 29. Thus, the coil 48 is connected across Vthe interpole winding 4 through conductors I6 and I8, and conductors 21, 28 and I9. The winding 48 is so wound that shouldthe voltage of generator I decrease to a value below' that of the bus lines 28 and 2| so that there isa reverse ow of Lcurrent from thebus'lines to the Y generator. thon themaenetic lllX.v of,A the ourront 76,604 I i "Y 4 netic force applied to switch arm 43, causing the same to open under the spring force of the switch arm 43. Upon switch arm 43 opening contact 45. the electromagnet 24 is deenergized whereupon switch 22 under spring force disconnects the genv erator from the bus lines 28 and 2 I. Y

The generator I is controlled by a Voltage 1 regulator I3, including a variable resistance carbon pile element 58 connected at one end by an electrical conductor 5| to terminal I2 and through the conductor to the positive output terminal B ofthe generator The opposite end of the nvariable resistance element 58 is connected by vconductor 52 toa terminal 53 of the regulator I3. A conductor 54 leads from the terminal 53 'to'v the terminalA of the generator I and thereby to the field winding 3 of the generator I.

Thus the carbon pile 58 regulates the excitation of the leld winding 3 of the generator I. The resistance of the carbon pile 58 is regulated by suitable electromagnetic windings arranged so as to .control an armature 51 and thereby. the pressure applied to the carbon pile.58 and the Vresistance thereof. Y Y The regulator is shown diagrammatically in the drawing as. including the armature 51 pivoted at 58 and exerting a compressive force upon the carbon pile 58 under tension of the spring 59.

.The spring 59 is arranged so as to balance the v electromagnetic forceapplied on the armature 59 .by an electromagnetic winding 38 when energized .by a .voltage having a predetermined valueand is `preferably of a type such as .shown lin U. S. Patent No. 2,427,885., granted to William G. Neild. 35 ...The coil 58 is .connected at one end by a conductor v(il to the .terminal 28 and through conductors 21, 28 and I9 tothe terminal E ofgenerator -I. The opposite end of the winding Y88 is confnected bya conductor 82 to a terminal 83 .which 0 in turnis Yconnected by a conductor .84 to the positiveoutput. terminal B of the generator I. Thus the coil68 responds to output voltage .of the generator.- and `is arranged. t0. regulateV the carbon pile 58 so as to control the excitation ofthe .field .Winding 3 of the generator to maintain a prede- VAtermined.generatoroutputvoltage. A second Aelectromagnetic winding 85 is vprovided for varying thedatum or voltage setting .of thewinding. The Awinding 65 has one end connected,l by a Vconductor 68 Vto a terminal ..81 vwhichis, connected by a conductor 68 to aterminal 89 of the control relay I5. .o The terminal 69 is connected by a conductor 18 -to the spring switch arm 38A controlled by the electromagnetic winding 38. The switch arm 38A is arranged to close a contact 18A upon the voltage-offthe generator I- reaching the predeter- `minedvalue. `The contact 18A is connected'by conductor `18 to `a terminalTI which is in turn connected by a conductor 12 toa manually oper'- "able'switch 13. The switch 13 controls a contact `14 connected by conductor 15 t0 an equalizer bus line'16fo a purposeV which will' be explained.

V'Iheswit'ch arrnv 36A may if desired be controlled by a separate relay indicative of a predetermined generator voltage.

l The other, edof the compensating boiij's's' is connected by a conductor 11 to van arm I18 of a r potentiometer and contacting thepotentiometer coil 19 at a point intermediate thevoppositeends .tltoroot. The.opposite ends ofthe potentiometer will?, arev4 connected .to terminals .l landb. rer

spectively, which in turn connect thegpotgntigmcoil 4s win be such as to decreasethetotalmeen;75.1eterscoil lacross the nterpo1e..;oomnensating winding 4 through lconductors I6 and 21, respectively.

The parent application Serial No. 621,515, filed October 10, 1945 is directed to a system in which a plurality of generators I; IA; IB and IC are provided. Each of the generators IA; IB and IC has a regulator similar to the regulator I3 of the generator I and indicated herein as ISA; ISB and ISC respectively. Likewise the generators IA; IB; and IC have control relays similar to the control relay I5 of the generator I and indicated herein as IBA; IEB; and IEC, respectively. For simplicity of illustration, the control and regulator circuit for the generator I only has been shown and the corresponding connections for the control and regulator circuits of the generators IA; IB and IC have been indicated by like numerals bearing a letter A; B or C corresponding to the respective generator to which the same relates.

rihrough the arrangement of the potentiometer "I9 across the interpole compensating winding 4, the coil 65 connected thereto through conductor I1 is responsive to the voltage drop across the Winding 4 so as to decrease or increase the voltage setting of the regulator I3 dependent upon the relative outputs of the several generators.

The coil E5 is further connected to a similar coil in each of the regulators ISA; ISB and ISC through the equalizer bus 'I5 and conductors 68A; 68B and 68C and conductors 15A; 15B and 15C and their respective relay controls ISA; ISB and I 5C, respectively.

The winding in each of the respective regulators ISA; ISB; and I 3C corresponding to the Winding 55 in regulator I3 is so designed that upon the generator controlled thereby assuming a greater portion of the load than the other generators the voltage drop across the winding 4 of the first mentioned generator will exceed the voltage drop across the winding 4 of the several other generators, whereupon a current will flow in the coil 65 of the regulator for the iirst mentioned generator in a direction causing an increase in the magnetic force acting upon the armature 5'! and increasing the resistance of the carbon pile 5D so as to reduce the voltage produced by the generator controlled thereby. This action will be readily apparent from Figure 2.

The direction of current iiow through the compensating coil S5 of the other generators, however. will be in such a direction as to counteract the electromagnetic force of the main control winding S so as to cause the spring 59 to draw the armature 51 in a direction for decreasing the resistance of the carbon pile I) and thereby increase the voltage produced by the generators controlled by the same until the generators are in a balanced relation.

The voltage coils 6B of the regulators I3; ISA; ISB and ISC of the generators I; IA; IB and IC are so calibrated as to regulate their respective generators so as to maintain substantially the same voltage, while the corresponding relays I5; I5A; I5B and I5C are arranged to connect their respective generators into the bus lines and 2l when their corresponding generators exceed that or the bus lines 20 and 2| by the predetermined diferential previously explained.

Thus, the generator rst reaching the predetermined differential above that of the battery or bus will be connected into the same.

When any other remaining generator has a voltage suiiicient to close the equalizer circuit through switch 36A, the unbalance in voltages tends to decrease the voltage of the nrst generator and increase the voltage of the second generator due to the fact that the rst generator is connected to the load so as to produce a voltage across the interpole compensating winding, while the second generator which is not connected to the load has a negligible voltage across its interpole compensating winding so that the current flow in the equalizer circuit is such as to decrease the voltage of the rst generator and increase the voltage settting of the regulator for the second generator. Thus, upon the voltage Agenerator increasing to a value above the bus voltage by a predetermined differential, the second generator is connected to the load.

The other generators are connected into the load in a similar manner.

During operation of the generators should vone tend to overheat the interpole compensating winding may be so designed as to increase its resistance with increase in generator temperature and thereby cause an increase in the voltage drop across the interpole compensating winding 4 causing in turn a flow of current in the equalizer circuit in a direction tending to increase the resistance of the carbon pile 50 and thereby produce a division of load by the several generators so that the generator which is overheated assumes a smaller portion of the load than the remaining generators.

Upon any one of the generators experiencing a decrease in voltage below that of the bus or battery so that there is a reverse ilcw of current towards the generator, the later generator will be disconnected from the bus or battery by the action of the reverse current coil 48 which is connected across the interpole compensating winding. Upon arm 43 opening the contact 45 the line switch coil 24 is deenergized causing line switch 22 to open.

Upon opening of line switch 22 there is a negative differential voltage impressed upon coil 38 which tends to cause a further decrease in the pull upon contact arm 43 so as to insure the maintenance of the same in open position.

In Figure 2, there is shown a somewhat modied form of the invention in which there is provided an external resistor 4A in place of the interpole compensating winding 4 previously described. Like numerals on Figure 2 indicate corresponding parts to those previously described with reference to Figure 1 and the interconnection of the compensating windings 65 for the generators I and IA are shown in greater detail.

The control relay for generator IA has been omitted for purposes of clarity and its operation will be readily understood when considered with the explanation of Figure 1.

Although only two embodiments of the invention have been illustrated and described, various changes in the form and relative arrangements of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a denition of the limits of the invention.

What is claimed is:

1. A device for controlling the connection of a generator to a load circuit, comprising, in combination, a control member, operating means for said control member including a first electromagnetic winding responsive to generator voltage and a second electromagnetic winding responsive to the difference between the generator and load current conditions, said second Winding arranged so as -to' assist said. first winding inactuating said control member to a generator connecting position upon said generator current exceeding said load current by a predetermined value, a switch member for opening and closing the energizing circuit of said second winding, an electromagnetic wind- -ing responsive to generator voltage fora'ctuating -rst switch member including a rst electromagnetic winding adapted tobe energized by the generator voltage, a second electromagnetic winding adapted to be energized by the difference between the generator and load current conditions, a second switch member, operating means for said second switch member including a third electrolmagnetic winding adapted to be energized by the generator voltage, said second switch member controlling the circuit, to said second electromagnetic' winding and arranged to close said last mentioned circuit upon a, generator voltagel in excess of a predetermined value, said secondY electromagnetic winding arranged so as to act accumulatively with respect to said rst electromagnetic winding so as' to close said first switch -memberruponl said generator current predom-T inating, said rst switch member controlling the circuit to said second electromagnetic winding and arranged so as toY shunt said second electromagnetic winding upon actuation to a closed position, afourthelectromagnetic winding adapted to be energized by the current flow through .said load circuit and arranged so as to tend to maintain said first switch member in a closed position while said generator current predominates and to effect the -opening of said first, switch member upon said load current predominating so as to disconnect said generator from the load circuit.

3. Apparatus for use in controlling the connection of a generator to a load circuit, comprising a main contactor for connecting said generator to said load circuit, an energizing circuit for said contactor, relay means for controlling the energization of said circuit including a i'rst electromagnetic winding responsive to generator voltage, a second electromagnetic winding responsive to the difference in voltage between said generator and said load circuit, control means for energizing said second winding upon said generator voltage exceeding a predetermined value, said second winding being shunted upon said contactor connecting said generator to said load circuit, and a third electromagnetic winding responsive to the direction of current flow of said generator to coaci-J with said rst ,winding to aid when the generator current predominates and to oppose When said load current predominates so as to disconnect said generator from the load circuit.

WILLIAM R. HOLMES.

REFERENCES CITED UNITED STATES PATENTS Name Date lreser Sept. 1, 1936 Number 

